In recent years, significant effort has been devoted to develop nanotechnology-based approaches for drug delivery since it offers a suitable means of delivering small molecular weight drugs, as well as macromolecules such as proteins, peptides or genes by either localized or targeted delivery to the tissue of interest. Several engineered nanomaterials such as dendrimers, liposomes, and metallic nanoparticles have been developed to deliver anticancer drugs to cancer cells. These systems in general can be used to provide targeted (cellular/tissue) delivery of drugs, to improve bioavailability, to sustain the effects of the drug/gene in target tissues, to solubilize drugs, and to improve the stability of therapeutic agents against enzymatic degradation (nucleases and proteases), especially of proteins, peptides and nucleic acids drugs. However, considering the molecular heterogeneity of diseases such as cancer, there continues to be a tremendous interest in the development of drug delivery systems capable of loading and delivering multiple therapeutic agents in order to achieve a synergistic therapeutic effect against aggressive diseases such as brain and breast cancers.
There is a continuing need in the medical arts for new carriers for therapeutic agents, particularly multiple agents, in order to deliver these agents simultaneously in a therapeutically effective dose and in a site-specific manner.